Pointing to problems with textbook arrows

Author

You’ve probably encountered at least one diagram in a biology textbook that didn’t make any sense to you. Although these pictures are supposed to clarify ideas, sometimes they leave readers befuddled. This is a particular problem for students; experts looking at schematics are able to fall back on their knowledge of a subject, while novices cannot. To help students learn, textbook illustrations must be as clear as possible.

In a paper published in CBE-Life Sciences Education, Wright et al. examined the use of arrows in biological diagrams. They looked at two introductory textbooks and found a wide variety of arrow styles used—including fat, skinny, dashed, and curved—to convey many distinct meanings—like chemical reactions, movement, and energy transfer. They found that many arrow styles were used to represent different processes throughout the textbook, and often, arrow styles were used inconsistently within sections, or even within a single figure.

Could the inconsistent use of arrow styles be contributing to students’ confusion? The authors conducted surveys and interviews with undergraduates, concluding that, yes, students are often uncertain about the meanings of the arrows. They found that most arrow styles don’t have any intrinsic meaning to students, and while some individuals correctly make inferences from context, many end up being unnecessarily confused by the use of arrows.

This study highlights a common problem in life sciences education: ideas that seem intuitive for experts can be problematic for novices. For a professor who has been up to their neck in biology for decades, it can seem obvious that a “bouncing” arrow represents phosphorylation, but for students at the start of their education, it’s far from intuitive. The authors recommend that instructors take the time to work with students on increasing their visual literacy and discuss the common representations used in their fields to maximize understanding.